No Health Without Zinc

Michael Martin looks at the benefits of the metal to human well-being.

The markets rightly consider zinc in terms of galvanized coatings, die castings, and brass. Public infrastructure, industrial and residential construction, automobiles and consumer durables are the major end-use markets, taking over 80% of the 11 million tonnes consumed each year, including recycling.

Zinc's discrete role in human health comes as a surprise to many people. In North America and Europe, food supplements and cold cures have appeared on the market in recent years, often supported by TV and magazine advertising. Doctors have begun to tell pregnant mothers about the importance of zinc for healthy babies and magazine articles have set out to explain that adequate zinc intake is part of a healthy diet.

Why all this interest in zinc and health? The reason is that an immense amount of research has been taking place over the last ten years or so, on the role of zinc in the human body. The Boston University School of Medicine set the tone when it stated in a 1995 report that "there is considerable evidence that zinc deficiency in humans is a serious worldwide problem." We now know, for example, that zinc is essential for our immune system, for reproduction, growth, wound repair, taste and smell. An often quoted fact is that the human body on average contains no more than 3 grams of zinc, but this tiny amount ensures the proper functioning of more than 300 enzymes.

The interest in zinc began over twenty years ago when researchers discovered a link between low zinc diets and stunted growth in children. Today, zinc would probably have 'wonderdrug' status if it could be patented.

Recent analysis of diet and nutritional needs have led researchers to estimate that a staggering 48% of the world's population is at risk from zinc deficiency. The percentage at risk is even higher in the poorer countries of South and Southeast Asia and sub-Saharan Africa. Furthermore, 33% of preschool children in low-income countries have stunted growth, increasing their risk of illness and mortality. Even in the United States, one of every two children studied was found to have zinc intake below recommended levels.

"Infants, young children and pregnant and lactating women have especially high risk of zinc deficiency because of their elevated requirements for this essential nutrient," says Dr Kenneth Brown, Professor of Nutrition at the University of California and one of the world's leading zinc experts. "Diets based predominantly on plants and vegetables have relatively low zinc content and poor zinc absorption", he explains.

The well-documented effects of severe zinc deficiency are growth retardation and stunting, changes in neuro-behavioural development, impaired reproduction and immune disorders. Research with volunteers on a very low zinc diet was recently stopped when it was discovered that the lack of zinc was causing heart problems. Mild zinc deficiency is more difficult to diagnose, although symptoms such as dermatitis, loss of appetite and slow wound healing are the telltale signs. Fortunately, all these health problems improve rapidly when adequate zinc is restored.

The really dramatic news, however, was highlighted at an international zinc and health conference in Stockholm, Sweden last year, organised by the International Zinc Association. Doctors, nutritionists and healthcare specialists from 37 countries came together to share experiences with zinc. Beyond any doubt, it is now clear that zinc supplementation reduces the risk and incidence of the most common childhood diseases in developing countries, such as diarrhoea, dysentery, pneumonia and malaria. According to the World Health Organisation, these are the very illnesses that account for 70% of childhood deaths worldwide. In addition, adequate zinc intake reduces the risk of complications during pregnancy and helps to ensure higher birthweight, healthier newborn babies.

The World Health Organisation now recognizes that zinc deficiency is a global public health problem that may have been underestimated. "The beneficial effects of zinc supplementation on health have been extensively demonstrated." says WHO's Dr Bruno de Benoist. "The next step now", he says, "is to look for the additional information required to provide countries with guidance on how best to alleviate zinc deficiency."

It is in this context that the International Zinc Nutrition Consultative Group (IZiNCG) was formed last year. IZiNCG's primary objective is to help reduce global zinc deficiency, particularly among vulnerable population groups in low-income countries. Supported by International Zinc Association, UNICEF, United Nations University, the International Union of Nutrition Scientists and other organisations, IZiNCG is working with governments, international bodies and NGOs to develop nutrition programs that will improve zinc status.

Several approaches can be used to improve zinc levels in populations at risk. The options include changes in crop agriculture to boost the zinc content of common cereals, food science technology and changes to cooking methods, nutritional education to improve diets, and administering zinc supplements. Another technique, used in countries as far apart as Mexico, Indonesia and Peru, is fortification of foods with zinc. In Mexico last year, for example, government and flour millers worked together to establish a voluntary code for fortifying wheat and corn flour with zinc.

What does this mean for the zinc industry? In terms of tonnage, the impact is nil. If all the world's population were to take a daily zinc supplement, the extra amount would barely justify the production of a small zinc mine. Nevertheless, International Zinc Association and its partners are sponsoring IZiNCG, numerous zinc and health conferences around the world and Z.I.N.C. - the Zinc Information Nutrition Center, a public-interest information service based at the Rockefeller University in New York in association with the Cornell Medical School. "This is about social progress," says IZA's Dr Edouard Gervais. "Many zinc producers already sponsor community development initiatives. Our support for zinc and health programs is another level of the industry's commitment to social responsibility and part of our sustainable development policy."

And if you think you are not getting enough zinc? Before reaching for the jar of zinc pills, try putting more zinc-rich foods in your daily diet, such as oysters, liver, beef, cheese and milk powder.

 

More information about zinc and health can be found at:
www.zinc-health.org and www.izincg.ucdavis.edu

This article first appeared in the July 2001 issue of 'The Ringsider', the magazine of the London Metal Exchange.